text:
Do any aircraft have a "self-contained ILS"?
The ILS is an invaluable aid to pilots, especially those operating to/from the many airports where poor weather is common (low-visibility operations would be completely impossible without an ILS); however, ILSs are expensive and maintenance-intensive, with the result that many smaller airports lack ILS capability.  Also, the requirement for a considerable quantity of pre-emplaced infrastructure obviously precludes one from performing an off-airport instrument landing.
On the other hand, the technology is available to guide an aircraft down to a precision landing at an arbitrary point on the ground, and much of this technology is already mandatory equipment on aircraft; GPS (which most if not all aircraft already have anyway) could be used for horizontal positioning and guidance and for plotting a landing route about the local terrain, the radar altimeter (also standard aircraft equipment) would provide vertical guidance, and a forward-looking radar system (also already standard, in the form of the aircraft's weather radar, which should only require an additional driver or two to add a terrain-sensing mode) would allow fine control of the aircraft's flightpath for the landing itself (where GPS, with its ~10m CEP, is insufficiently precise and accurate for a safe touchdown) and allow the aircraft to orient itself in space (as GPS tells the aircraft where it is, but not which direction it's pointing).  Additional equipment that would be useful and could easily be added would be a second weather radar (to allow the pilots to continue to monitor the weather even with one radar in terrain-mapping mode), a Doppler radar system (to warn the pilots of dangerous windshear, microbursts, etc.), and a forward-looking lidar system (to provide advance warning of clear-air turbulence along the approach path).
With the appropriate software, these instruments could be used to plot and fly a safe instrument landing at a noninstrumented airport, or even at a non-airport; this latter capability would be extremely useful for medevac and SAR pilots (whose duties, by their very nature, involve operations to and from off-airport locations, frequently in poor weather) and for military helicopter pilots (same reason).
Are there any aircraft already equipped with such a "self-contained ILS"?

Why on Earth would you think that most aircraft have radar altimeters and forward-looking radar?  Or radar of any sort?  And how much is this going to cost me, and is the weight more than my Cherokee's payload?

This question editorializes about varied needs and technologies, but asks the question about "self-contained ILS." Perhaps the extended discussion distracts from the key question, about a self-contained guidance system, which has very specific functionality.  In fact the ILS functionality is much more limited than the broad discussion that precedes it.

GPS is not mandatory equipment

Radar alts and radar are not standard equipment.  Where did you hear that it was???

Recommended reading: 2019 Federal Radionavigation Plan.  It covers the systems currently available and  future planned systems.

Approaches guided by GPS are called RNAV; it can provide both lateral and vertical guidance, in some cases to the same precision as ILS Cat I, without need for a radar altimeter--which is not standard equipment. (There are also non-GPS ways of using RNAV, which are mainly used by older airliners that haven't been upgraded yet.)
Note that standard GPS has accuracy of 100m; SBAS (aka WAAS) gets that down to 7.6m.  Both are standard in aviation GPS units these days, and GBAS (aka LAAS) will eventually get that down even further.
There are already three times as many RNAV approaches as there are ILS approaches with more appearing every day, and most aircraft are now equipped to use them or probably will be soon. IOW, the essence of what you propose is already here.
Instrument approaches do have to be pre-planned to ensure obstacle and terrain clearance, so airplanes can generally only use them to land at airports. (The rules are different for rotorcraft, and that's generally what you'd use for rescue, but I'll have to leave the specifics to someone else.)
Many large aircraft carry weather radar, but it's too heavy for light aircraft; both can use satellite weather data services, in addition to getting weather updates via radio the traditional way.

Can't obstacle and terrain clearance be guaranteed by using GPS, the radar altimeter, and a forward-looking radar?  An aircraft's GPWS (required by law in all countries) uses all of these to keep you from flying into the ground when you don't want to; presumably, they would be just as useful for guiding you to a landing on the ground when you do want to.

@Sean: GPWS (Ground Proximity Warning System) is not required on all aircraft, only (per Wikipedia) turbine-powered aircraft with more than 6 passenger seats.

GPWS only looks straight down, so it can't detect sharp rises in terrain--and it is disabled when the aircraft is in a landing configuration anyway. EGPWS adds a terrain database and GPS lookahead, but it still only covers terrain; adding every man-made structure on Earth (and keeping it all up to date and distributed to every aircraft in a timely fashion) would be completely unmanageable.

For an example of an inhibited GPWS contributing to an accident see https://en.wikipedia.org/wiki/2010_Polish_Air_Force_Tu-154_crash

RNAV is not limited to GPS approaches.

@Stephen Sprunk, what sat weather data services are you referring to for light aircraft?

Sirius XM WX is well known; there may be others.

You don't need nearly all the equipment you mention. A great deal of aircraft are capable of flying GPS/RNAV approaches from big boys down to the little Piper Archer I fly. Units as small as a Garmin 430 are capable to providing all the facilities you need to fly GPS/RNAV approaches. If your unit has WAAS capabilities you can fly to even lower minimums.

This does exist, and is used by US military aircraft. It's called a Self-contained Approach (SCA) or Independent Precision Radar Approach (IPRA). The primary user of these approaches is Air Force Special Operations Command on aircraft like the MC-130 and AC-130.
Regulatory guidance is contained in the AFI 11-202v3 AFSOC Sup, section 7.4, and operational procedures would be governed by the applicable AFI 11-2MDS volume 3 or another MDS-specific publication, which may be a controlled item.
Shooting one of these approaches involves the flight crew looking for obstacles or obstructions; choosing the planned glideslope, and creating the plan, including update, missed approach, and descent points.

Thanks for the answer. This sounds great for emergency or tactical use. Is there an equivalent for civilian use? Would this still be considered a precision approach?

I've never heard of anything similar in the civilian world, and doubt there is anything (not all military aircraft have the capability, and since even fewer civilian aircraft, if any, have the radar needed to perform this, I doubt there is anything there. I guess you'd call it a precision approach, since it has glidepath guidance, but really it's in its own category of approaches

An ILS approach consists of a minimum of a localizer and glide slope transmitters. Both transmitters are ground based, in a fixed location.  While the creation of some other reference point, using GNS or even inertial navigation might be possible, it does not directly emulate ILS.
Furthermore, if one were to recreate the references to a landing zone using some other form of navigation, it is likely that the exact emulation of a localizer and glide slope might not be exactly emulated.  Consider that MLS was intended to be an ILS substitute, and it offered a variety of localizer courses, and a variety of glide slope paths.
While it is true that self contained navigation systems, including INS, and even varied techniques such as radar mapping, or even IR lidar mapping, could be employed, it is unlikely and perhaps inefficient to have them emulate what an INS does.  Therefore the likelihood of a "self contained ILS" appears to be very close to zero.
While there are many systems and methods which will navigate to a given point, with the potential ability to align an aircraft for a landing, they do not match the essentials of an ILS, which is two ground based transmitters, one with lateral and the other with slope (vertical) guidance.
Finally, if one wants to consider self-contained navigation approaches, a study of missile guidance will yield scores of self-contained, and externally augmented approaches.


text:
Is this planned building in a runway approach legal?
A 50 story building is planned in Santa Clara, CA three miles from the SJC 12R runway end. Such a building is at least 500ft tall and many such buildings are 700ft or more, is this legal? Nothing around it is more than 100ft tall. Taller than 200ft qualifies it at least as an obstruction.

Just as an interesting side note check out the story in my answer here

@TomMcW The powerline story was pretty great.

Can you add a source or background information for the building project please?

From Dave's part77 reference a precision approach surface has a 50:1 slope to 10,000ft out and 40:1 from there to 50,000ft out. Width is 1000ft at runway and
16,000ft at terminus.
The runway has a 1300ft displaced threshold plus just less than three miles to the building puts the distance at 17,000ft. 50:1 for 10kft is 200ft plus 40:1 for 7kft is 175ft which makes the approach surface 375ft high as it passes the building.
Surface width from center line at that point is 17k/50k*8k or 1000ft. The building looks to be 2500ft from runway centerline, so it is 1500ft from the precision approach surface edge. The side slope at that point is 7:1 for 1500ft or 214ft. Adding this to 375ft makes the allowable height about 590ft, so the building could fit below the limit for construction. It would have to be lighted as an obstruction.

Yeah, looking at Google Maps and using the measurement tool, it appears that the building (if the pin location on the map here is accurate) is about a third of a mile from the extended centerline of the runway. As a side note, there are already several tall buildings that aircraft fly pretty close to on arrival into SJC from the South.

If it falls within the limits set out by FAA FAR Part 77 then its legal. You can find a nice breakdown of Part 77 here but you would need measurements more precise than what google maps is going to give you to be sure. Depending on the height the FAA may also require them to light the top of it. This is actually an interesting break down as the FAA is a federal organization and building approval generally comes down at the city/town/municipality level. If a building is approved for construction by a city one can assume it is legal to be built and that the city accounted for the FAA regulations. According to AC 150/5190-4A which quotes the Airport an Airway Improvement Act of 1982 it looks like its on the city to ensure that nothing gets in the approach path:

...Sec. 511 (a) SPONSORSHIP. As a condition precedent to approval of an
  airport development project contained in a project grant application
  submittted under this title, the Secretary shall receive assurances in
  writing, satisfactory to the Secretary that ... (4) the aerial
  approaches to the airport will be adequately cleared and protected by
  removing, lowering, relocating, marking, or lighting or mitigating
  existing airport hazards and by preventing the establishment or
  creation of future airport hazards; (5) appropriate action, including
  the adoption of zoning laws has been or will be taken, to the extent
  reasonable, to restrict the use of land adjacent to or in the
  immediate vicinity of the airport to activities and purposes
  compatible with normal airport operations, including landing and
  takeoff aircraft; ...."

In other words, the city needs to have zoning laws that keep the approach path clear. This is largely covered under the above linked Part 77 but generally speaking if the building has been approved its more than likely legal as per approved zoning laws.
A bit of a related story: you should not put it past people to build out of spite. A farmer once built a silo right off the end of Chatham Airport's runway to try and stifle traffic that he claimed was buzzing him while he was working. The silo is now gone and I cant find any info on what happened to it but this was also some time ago and I dont know what the regulations were when it happened.
And in some rare cases, if there is something in your way, an approach can be devised around it.

I already knew it qualified as an obstruction, but I couldn't find anywhere what that meant legally. Does it just need lights or is it prohibited? And do you know what happened to the silo? It's gone.

Do you believe the site owners and architects are totally unaware of the airport? or are maliciously building an illegal building?  It strains credibility to believe the building is illegal; if it were illegal, it wouldn't move past the artist's sketch.   The better question is, Clearly, such a building is permitted:  Why and how is it allowed?

@abelenky Chicago tore up Meig's field in the middle of the night. Was that legal?

@Pilothead I did some more digging and added a bit, hope it helps to clarify.

It's not unheard of for a City to issue a building permit without first having cleared the building through the FAA.  This exact thing happened near Montgomery Field in San Diego although not directly in line with the runway, but in the traffic pattern.  Big lawsuit ensued.  Net result was the building had to be partially "de-constructed" and lowered a bit.  The City maintained federal regulations were outside its purview and the developer "should have known" to check with the FAA.  Developer said a building permit was supposed to include all regulations.  Not sure who won.

@pjnoes  When did this happen and which building? I hadn't heard that story before.

@Todd about 10 years ago.  Here's a link to the local story at the conclusion of the lawsuit:  http://www.sandiegouniontribune.com/sdut-1m19sunroad23225-sunroad-suit-versus-city-tossed-2009may19-htmlstory.html

Standard climb rate is 200 feet/nautical mile.  So 500 ft at 3 miles, = 2.6 nautical miles, could see some slow climbing aircraft passing pretty near by.
The airport should be taking steps to work with the city planning board or AOPA or something to prevent future outcries from the building occupants over planes passing near the tower.

It may be more critical on landing.

Yes, it could interfere with IFR approaches.  Course, they could always raise the minimums and make it a Circle to Approach landing.

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Has an airplane ever been launched from a submarine?
Airplanes are routinely launched from ocean going vessels, namely carriers.

Missiles are routinely launched from submarines.

Has an airplane ever been launched from a submarine?
From questions about what qualifies:

Manned or unmanned is ok, but payload mass has to approximate a least a small person
One way trip is ok
Airboat dropped in the water is ok
Airbreathing primary propulsion required, rocket assist for takeoff is ok
Wings for lift are required, control fins alone do not qualify

Technically a cruise missile is a disposable aircraft (jet engine and wings, if unmanned) and modern variants can be tube launched while submerged.  Presumably the same could be done with a UAV.

@ChrisStratton A cruise missile as you describe would qualify if you can find one that actually comes from a sub. I've seen them from cruisers and destroyers.

Tomohawk would be the obvious example, with both horizontal and vertical sub launch, as well as surface ships.

This list, https://en.wikipedia.org/wiki/List_of_submarine-borne_aircraft seems on point...

"Submarine aircraft carrier", Wikipedia.

How can this be a well researched question when (as pointed out by others) there is literally a wikipedia page on this very subject?

Yes,
The HMS M2 had a single seaplane aboard that it was capable of launching.

Her 12-inch gun was removed, replaced by a small aircraft hangar, the
  work being completed in 1927. This could carry a small Parnall Peto
  seaplane, specially designed for the M2, which, once its wings had
  been unfolded, could be lowered onto the sea alongside by a derrick
  for take off. On landing, the aircraft was hoisted back onto the deck
  and replaced into the hangar.

...

In October 1928, a hydraulic aircraft catapult was fitted, to enable the seaplane to take off directly from the deck.

The I-400 class submarine was also capable of aircraft launches.

The type name was shortened to Toku-gata Sensuikan (特型潜水艦 Special Type
  Submarine). They were submarine aircraft carriers able to carry three
  Aichi M6A Seiran aircraft underwater to their destinations. They were
  designed to surface, launch their planes, then quickly dive again
  before they were discovered.

There are some more info blurbs here worth checking out about various submarine/aircraft creations.

"once its wings had been unfolded, could be lowered onto the sea alongside by a derrick for take off" Would seem that the aircraft was only stored on the submarine, not launched from it, although the OP would have to decide if it fits his definition of "launched from" or not. The Japanese one seems to fit the description though.

If you are willing to extend "aircraft" to include cruise missiles, the Regulus and Tomahawk missiles were launched from subs, the latter while submerged.

Are you sure 12 inch isn't a typo? That's a big number for submarine guns.

@RonBeyer Putting a boat in the water is considered launching so putting an airboat in the water has to follow, though this is not what I was originally thinking.

@Joshua not typo.  These early 1920s era submarines had dive times of 5 minutes or less... They had to function as battleships.  That 12-inch gun is actually the same gun used in Formidable-class battleships of the Royal Navy.

@Nelson "Dive times of 5 minutes or less"  What do you mean by this?  That it took them less than 5 minutes to submerge, that they could only remain submerged for 5 minutes, or something else?

Actually I did misread the dive time. It does mean it takes 5 minutes to dive. However, the thought back then is to use guns and they functioned as battleships that can submerge. Torpedoes were not reliable yet.

An underground aircraft launch can be seen about 30 seconds into this video sequence, dated 1980.  https://www.youtube.com/watch?v=US7IF31wDVM

Back in the late 1980's I visited the wreck of the M2 just a short distance from Portland, Dorset.  As a naval grave site it is not legal to enter the structure but it was quite impressive even though the underwater visibility was only a few metres.

Was the hanger capable of keeping the plane dry when the submarine dived? Or if they were faced with danger before they had launched the plane, did that mean they had to choose between wrecking the plane and staying on the surface?

The French Surcouf also carried a floatplane, to spot for her twin 8-inch guns. And @Paul; depends on your definition. All these boats were designed to protect the aeroplane from water while submerged; none of them did so reliably enough for me to act as pilot.

Wow already in 1927. That must have been a feat.

Also consider the Japanese I-400 class submarine, that carried three Aichi M6A Serian bombers. Probably the most advanced aircraft carrying submarines ever built.
They entered service too late to have any meaningful impact, but the engineering that went into them was amazing for its time. Just designing a submarine that could carry a watertight aircraft hangar without the topside weight capsizing the submarine was no simple feat. They built preheaters for the aircraft engines into the submarine, so the submarine didn't have to linger on the surface while the aircraft warmed their engines.
There was a plan to attack the Panama Canal locks with torpedos launched from the Serian aircraft, but it was never carried out.

note that the I-400 was already mentioned by Dave's answer.

Plus, the U-Boot-Klasse VII could launch a "Bachstelze" somewhere near the end of the war, too.

Also this (https://en.wikipedia.org/wiki/Japanese_submarine_I-25) the only bombs to be dropped by the Japanese on the continental US were dropped by a float plane launched from a submarine.

If you allow "airplane" = "unmanned aircraft"...then, jets!
There was Regulus 1

Submarine testing was performed from 1947 to 1953 at the Navy's
  facility at Naval Air Station Point Mugu, with USS Cusk (SS-348) and
  USS Carbonero (SS-337) converted as test platforms, initially carrying
  the missile unprotected, thus unable to submerge until after launch.

And Regulus II

...the only submarine launch was carried out from USS Grayback in
  September 1958

The air inlet on Regulus II always makes me think it's laughing for joy to be launched.

Unmanned is ok. Air breathing propulsion is required. Rocket assist for takeoff is ok.

I like these, but  where is the submarine?

The links explain that they were sub-launched.  Edited to include.

@Pilothead It's docked at Pier 86 in NYC

If a kite rather than an aircraft qualifies:
German U-boats used a towed autogyro to lift a lookout/pilot to a more advantageous altitude (about 120 m). https://en.wikipedia.org/wiki/Focke-Achgelis_Fa_330.
The strategy increased the visible range from 5 nautical miles to 25 nautical miles.  There is one recorded instance of a submarine detecting, attacking and sinking the Greek steamer Efthalia Mari on 6 August 1943.
If a hostile vessel was seen,

If the U-boat captain were forced to abandon it on the surface, the tether would be released and the Fa 330 descend slowly to the water.

I believe this might discourage reports of enemy warships by the pilot/observer.

 (Wikipedia)
I got beat to mentioning Regulus, but the Tomahawk cruise missile has been launched from a submerged sub.  A rocket is used to initially launch the missile.
 (reference)

And if you're going to complain about the "lack" of wings--those are wings on that missile.  It just has a very high minimum airspeed and thus can use very small wings.  They use a rocket booster to get them up to the speed where the wings will function.

Yes.
Here is a wikipedia article about many of the designs:
https://en.wikipedia.org/wiki/Submarine_aircraft_carrier
Most seem to have gone out of service before the end of WWII, but a German submarine, the Type 212, is being designed to launch UAVs out of its mast:
https://en.wikipedia.org/wiki/Type_212_submarine (see the last paragraph in the "Weapons" section).

Unmanned is ok but toys do not qualify. Payload capability of the aircraft has to approximate at least a small person.

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text:
What airplane is this? and why the strange inlets?
Why does it have such strange intakes?

@ymb1 It was a YouTube video that came up on autoplay. I didn't keep track of it. I will in the future.

@Pilothead ok but now that you know what the plane is, it shouldn’t be hard to find a properly licensed image that you can attribute. Also, the video will be in your YouTube history.

Better view.

That's a Polish Air Force MiG-29 "Fulcrum".  The strange intakes are to decrease the risk of foreign object damage during rough-field operations.
Edit to clarify: Normally, when the MiG-29 is in flight, the large ramp intakes below the wings are open, providing all the air for the engines, and the louvered intakes on top of the wings are closed.  However, if the aircraft is going to be operating from rough fields or flying at very low altitude, the pilot can close the main air intakes.  When the main intakes are closed, the louvered auxiliary intakes automatically pop open, so that the air going into the MiG-29's engines comes from above the aircraft, rather than below it; this greatly decreases the risk of the engine eating loose objects on the runway (that, and the fact that the opening a foreign object would have to pass through to enter the engine via an auxiliary intake is much smaller than the opening for the main intakes).  As the auxiliary intakes are smaller and at an angle to the airstream, the engines can't get as much air (and, consequently, can't produce as much thrust) when using the louvers as they can when using the main ramps; Mikoyan apparently decided that, for rough-field operations, decreased performance was an acceptable price to pay for a decreased rate of engine object ingestion.

Why not have such intakes on large jets also?

Not many jets are designed to take off from grass or gravel.

@Cloud Cost, weight, maintenance, and lack of operation from rough fields.

Regarding the thrust question, are the aux intake actually "much smaller" or are they just a lot less efficient at high speeds than the properly shaped and directed main intakes?

if you look up the top of the leading edge where the wings join with the fuselage, you can see some slats, the engines breathe through these slats when the main intakes are closed, which is mainly during takeoff and landing to reduce the risk of foriegn object damage to the engines. this allows for the russian built mig 29 fulcrum to be able to land on much rougher landing strips

Aren't the air-intake requirements higher at ground-level because the engines run at full-blast to take-off? If so then it's unusual that they're so small compared to the front intakes. Or are the front intakes bigger because at higher altitude the air is less dense so it needs a bigger cross-section?

@Dai Sure, but the risks of ingesting rocks are also higher when the engines are run at full blast to take off!

@DavidRicherby: Especially since, when the airplane is taking off, it is much more likely to be somewhere where there are rocks to ingest.


text:
What causes this much engine damage?
EASA and FAA have placed a 300hr inspection AD on select Dreamliner Trent 1000 engines after multiple failures. Here is a photo of an AirNZ engine.
https://leehamnews.com/2018/04/14/faa-ad-may-severely-limit-etops-of-rr-powered-787s-sources/#more-26889
Update from comment on reference article:
The AD specifically refer to :
Intermediate Pressure Compressor (IPC) Stage (Rotor) 1 blades
IPC Rotor 2 blades
IPC Shaft Stage 1-8 Rotor assemblies
Previous stories had RR ‘offloading 35% of the Trent 1000 development risk to its partners The IPC module is done by Kawasaki. This seems to be different to the other known issue on the Trent 1000 of the fatigue cracks of the Intermediate TURBINE
What causes this much damage?

Could be gremlins or it could be debris any more context to the photo?

December last year AirNZ to Tokyo had an inflight shutdown with this result. Apparently there was no damage to the fan, so they likely didn't hit anything. Separately there was a problem on a flight to Buenos Aires which didn't need a shutdown.

I'm not sure why you pasted an incoherent comment into your question. How does the comment relate to your question?

Report here states it is suspected to be due to foreign or domestic object damage (FOD/DOD).

Provided with the photos taken of the NZ99 engine after it landed back in Auckland, a spokeswoman said: "The cause of these incidents is yet to be determined and this is the role of the Transport Accident Investigation Commission. But the damage sustained on Tuesday suggests an engine part has travelled through the engine."
An aviation source told Newsroom: "The damaged blades are in the aft section of the turbine blade sections. It is likely the damage has resulted from a failure of a turbine blade or blades in an earlier section that has been spat out the back with a domino effect.”

I would suspect an over temperature and/or excessive vibration may also have occurred. It seems similar to the damage in these two events, which featured those events:
Boeing 777-200, GE90, Dec 2010.

The damage pattern leads to the suspicion that one or more fuel injectors in the combustion chamber behaved abnormally leading to an excessive temperature build up in the turbine area, which probably caused the LPT guide vanes material to fail. The engine manufacturer has registed six similiar failures which are all suspected to be the result of fuel injector malfunctions.

Boeing 737-400, CFM56, Nov 2009.

The in-flight malfunction of the aircraft’s right engine was a result of a cascading rupture of the stage-1 LPT blades, [which] was probably precipitated by thermal degradation of the blade alloy, resulting in excessive creep extension, tip shroud/seal interference and blade rupture. Material characteristics of some of the LPT blades installed in the engine were consistent with a raw material manufacturing cast that had previously been identified as being susceptible to creep rupture.

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text:
How does a self-centering rudder affect left-turning tendency?
In this answer to a question about controls, Peter Kämpf mentions the Klemm 35:

...the rudder has two narrow strips which are deflected slightly to the left and the right, respectively. This increases the force gradient over deflection for the first few degrees when the rudder is moved away from its centered position.

How does this interact with left-turning tendency coming from the engine slipstream? Normally, small movements of the rudder are needed to counteract the effect of the slipstream on the fin, so increasing the force required for small movements would seem to hinder rather than help the pilot.
On the other hand, I'd expect the right-pointing strip to be in the lee of the fin (as the slipstream passes left-to-right over it), which would reduce the force on it, letting the rudder move a little to the right on its own, which is exactly what you want.
What actually happens? Does the neutral position of the rudder change at different power settings when flying straight and level? Does this arrangement reduce your foot workload compared to other aircraft?

@rbp I don't understand your edit. Why only left? if it turns right it would not apply? (https://en.wikipedia.org/wiki/Adverse_yaw)

Except for some very old planes, all singles props turn CW and have a left turning tendency. See paragraph 3 in Phliar Phil's answer

Perhaps you forget that I fly an aircraft with a CCW prop, which has a right-turning tendency.

How could I ever forget about you @DanHulme? Your plane is a 1930s model, which i put into the category of "very old."  Its the same thing in Helis. Right pedal as you add power, unless you're in a Eurocopter, then its left. "step on the down-traveling pedal?"

Adverse Yaw created by the propellor will vary based on aircraft and design. Lots of modern single engine aircraft do things to counter act adverse yaw but if we take a pretty neutral aircraft design and apply the tabs you reference all you will see is a slightly more aggressive rudder. Since there is a tab in each direction in a centered situation they will cancel each other out however they will cause the rudder to have a more drastic impact at smaller angles of deflection.

What actually happens? Does the neutral position of the rudder change
  at different power settings when flying straight and level? Does this
  arrangement reduce your foot workload compared to other aircraft?

The neutral position of the rudder will always change a bit as the power settings vary. For this you have rudder trim. Generally speaking a lot of GA planes have a bit of left rudder trim always in to counteract P-Factor some even have permanent design features to do so. It should also be noted that P-Factor is most prominent at high angles of attack and high power settings (takeoff and climb out) generally this also means lower airspeeds. Once you settle into cruise its effects are decreased. I have never felt that it adds to my work load when flying but Ercoupe pilots may have a different opinion on that.... The design you mention does not really reduce workload, for that you would need something like a yaw damper some new planes like the Cirrus SR22 have them.

First, "adverse yaw" refers to the increased drag of a down aileron (and reduced drag on an up aileron) -- which mean that as you deflect the ailerons to roll left (in order to turn left), the adverse yaw makes the nose yaw right -- exactly the opposite of what you want. Therefore you balance any application of aileron with just the right amount of rudder to counteract the adverse yaw. This is called "coordination".
For any control surface (like rudder or aileron) there is a small "dead zone" around neutral, where movement of the surface does not have an appreciable aerodynamic effect. Those narrow strips reduce the size of that dead zone and improve control. Therefore they help, not hurt.
What you're talking about is what the FAA (and others) call "left-turning tendency". When flying straight and level, the engine power affects the amount of rudder required, and significantly so. At high power more right rudder is required, and especially so at low speeds like climbing. At low power settings less right rudder is required, especially at high speeds -- so in a descent many aircraft require left ruder to straight. (Of course this is most applicable to single-engine airplanes where the fin is in the propwash.)
To help the pilot with the forces required, surfaces have trim tabs -- see Why Pitch Trim Up/Down & Roll Left/Right switches on yoke or control stick?
(Incidentally, many older small English engines like the dh Gipsy engine, https://en.wikipedia.org/wiki/De_Havilland_Gipsy_Major, turn the opposite direction so airplanes like the Tiger Moth that use that engine have a right-turning tendency and require left rudder.)

You might want to add that on smaller airplanes those trim tabs are just fixed strips of metal at the trailing edge which can be bent (while on the ground) to trim the zero point of the control surface.

Thanks for the interesting tidbit about the airplane I fly. I feel like your second paragraph starts to answer my question, but I still don't really understand how (if at all) the self-centring changes the need to use rudder at different power settings.

It doesn't change the need at all -- no matter what improvements you make, you will need different amounts of rudder at different airspeeds and throttle settings. Unless you fly an airplane that has equal amounts of fin (vertical stabilizer) above and below the centerline.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
What are the "channels" on the A320 Rudder Travel Limit Unit?
The KNKT's final report on last year's Air Indonesia QZ-8501 crash repeatedly mentions that the faulty solder joint on the Flight Augmentation Computer (FAC) caused an open circuit on "both channel A and B", leading to the repeated failure of the Rudder Travel Limiter Unit (RTLU). (Page 66 of the report has a photo of the offending solder joint and of the whole module.)
What are these "channels"? The only relevant mention I can find in the report is on p37, an extract from the Flight Crew Operation Manual, as follows (ellipsis mine):

In performing these functions the FAC uses independent channels:

Yaw damper
Rudder trim
Rudder travel limit
Flight envelope

...
If  a  failure  is  detected  on  any  channel  of  FAC1,  FAC2  takes
over the corresponding channel.

Are the "channels A and B" two of the output "channels" mentioned here? The last quoted line suggests that each channel is redundant between the two computers, in which case why would both RTLUs fail together?

The problem is that you're using the Flight Operations Manual, and not the Schematic Manuals. Quite frankly, FOM's pretty much suck in terms of technical details, but that's not their purpose either.
In regards to your question about what the channels are:
Channels are really just a euphemism for system redundancy. The FAC's are two completely separate entities (with crosstalk capabilities) - kind of like flight crews. The PIC (pilot-in-command) has primary control of the aircraft, while the SIC (second-in-command) has the same independent authority. The PIC and SIC can talk to one another, and monitor what each is doing. If the PIC falls ill, becomes incapacitated, etc.. the SIC can take over the functions of the PIC.
The FAC's work the same way. They both receive the same information, and have full capability of performing the work of one another. Take note of this schematic, courtesy of Airbus (found on the web), and which I took the liberty of highlighting:

Basically, what this schematic is saying is that the ELAC's, under normal law, provide turn coordination and dutch roll damping to the FAC's. They do this by receiving inputs from the rudder pedals, sidesticks, FMGC's, ADIRU's, SFCC, LGCIU's, and hyd pressure. Based on those inputs, it computes the proper yaw commands and sends that to the FAC's. It should be noted that both FAC's receive the same information on, you guessed it, separate channels. What does that mean? The data from ELAC 1 is sent to BOTH FAC's on separate sets of wires. Inside the FAC's, those data paths are split as well (Channel A & Channel B) and a separate processor computes the data on Channel A & the data on Channel B. Never the two shall meet. Likewise, the data from ELAC 2 is sent to BOTH FAC's on separate sets of wires, and again, those two data paths shall never meet.
At the same time, both FAC's are receiving the same FMGC, ADIRU, SFCC, LGCIU data that the ELAC is. Again... Separate wires, separate outputs, and computed with two different processors inside the boxes. The FAC's are also receiving hydraulic pressure, commanded rudder trim position, and SEC fault data. Guess what? All on different channels.
Now, take note of the highlighted portion in red. Ordinarily, FAC 1 is in control of the servo loop for the RTL Motors. This essentially means that based on ALL of the inputs received from the ELAC's and other independent systems, the FAC 1 sends a signal to the rudder travel motor and says "Move here." The motor moves, and a feedback signal from the RTLU circuitry is sent to the FAC saying "Here I am." When the commanded position of the surface position minus the actual position of the surface is approximately ~0, the surface is nulled. This is a basic feedback loop/servoloop.
The FAC 2 has the exact same capabilities as FAC 1. The two are in constant communication, making sure that neither has failed. If FAC 1 reports a self-failure, or FAC 2 detects a problem with FAC 1 and/or its servo loop, FAC 2 can immediately take over.
Notice that FAC 2 is responsible for the M2 (second motor) of the rudder travel limit system, and FAC 1 is responsible for the M1 (primary motor) of the rudder travel limit system. The wiring for the motors and its associated servo loop are completely separate. Again, the idea is complete system isolation. As such, any one failure cannot take out the entirety of a system.
All of the above is under the presumption of NORMAL LAW. It appears that cracked solder joints, emphases on the plural form, caused failures of Channel A & Channel B of the RTLU (see page 66 of accident report). Basically, like I mentioned previously, FAC 2 was monitoring FAC 1 for faults with it or its associated servo loop. When RTL channel A failed (the servo loop feeding data back to FAC 1; associated with Motor 1), the FAC 2 picked up on it, and took over on its own separate channel. A cracked solder joint on RTL channel B caused FAC 2 to trigger a failure. At some point during these failures, the flight crew pulled the circuit breakers, presumably to reset the faults. The loss of both FAC's put the aircraft into alternate law.
Once the aircraft was in alternate law, it seemed that there was a lot of confusion as to what was happening. From there, things went from bad to disastrous.

Thanks for spelling everything out. There's just one detail at the end: the RTLU failures themselves didn't put the aircraft into alternate law. That only happened when the flight crew pulled the breakers for both FACs. The effect of both RTLUs failing is merely to leave the limiter stuck at its position at the time of the failure. It's spelled out later in the report.

Thanks for pointing that out, Dan. I missed that part in the accident report, and wasn't sure if the crew pulling the circuit breakers was media myth or not. You're also correct about the function of failed RTLU's. I have corrected my original post to reflect that, albeit on my iPad. So, if I missed something in the edit, I blame Apple. :-)


text:
What is the correct phraseology to request a climb?
If you'd like to request a climb to a higher flight level while cruising, which do you think is a more proper way to request it:

Request to climb FL350
Request climb FL350

I know they have zero difference in meaning between them, but I'm curious which one might sound more natural or professional in the EPTA test.

I would say that “Request climb FL350” is better.
I never use the word “to” in altitude requests as it can be confused with “”two” as in “request climb to seven thousand” (request climb two seven thousand)
If you get in the habit of using “to” with flight levels, you will probably use it in a baro altitude request as well.
I also leave out “climb” and just say “request FL350”. But, when ATC says “climb FL350”, I will read back “climb FL350”.

According to ICAO RTF manual (ICAO Doc 9432) the direction is omitted when requesting a level change.
So you would just say: ”FASTAIR 345, Request FL350” and then after receiving the clearance, you would use the ”TO” word: ”Climbing to FL350, FASTAIR 345”

"American one twenty three requesting flight level three five zero." Whether it's a climb or descent is known by the controller, because he/she knows your present attitude and altitude assignment.

For sure, the ATCo understands both, but there is the STANDARD phraseology to request it.
PIL: "REQUEST TO CLIMB TO FL 240."
ATC: "CLIMB TO FL 24O."
PIL: "CLIMBING TO FL 240."
Doc 9432 AN/25.

Got a specific page number in that document?

There is no such exchange in the document you refer to.

DOC 9432 contains many examples of how to use the word "request". In none of those examples is "request" followed by "to".

You can't go wrong with "XXX requests (or requesting) climb FL350". In practice you'll hear a number of ways of saying it, some more conversational than others, depending on how busy the comm freq is.
Also, if you are calling in from out of the blue looking for a significant change in your clearance like that, it's good etiquette to give Center a heads up by saying "Soandso Center, XXXX with a request", then follow up when the controller answers.

I never use the word “to” in altitude requests as it can be confused with “”two” as in “request climb to seven thousand” (request climb two seven thousand).

For a baro altitude request yes, but sticking the word "to" in a flight level request, which I tended to do without really thinking about it, doesn't have the same confusion problem as that, but your point is well taken and I edited my post.


text:
In what conditions do airline pilots favor crabbing over de-crabbing for crosswind landings?
There are several crosswind landing techniques described on Wikipedia, including crabbing (straightening out after touchdown) and de-crabbing (straightening out just before touchdown).
For airline pilots, are there specific conditions that favor the use of the crab method over the de-crab method for crosswind landings, despite the excessive side load the crab method may incur? When airline pilots use crabbing for crosswind landings, what are the reasons?
(This question is not about the general crosswind landing techniques dealt with in this great post but more about airline pilots' crosswind landing techniques. More specifically, my question addresses some possible conditions where the airline pilots would prefer the crab technique to the de-crab technique.)

Take the runway that better aligned into the wind.

Most airliners are low-wing, hence sideslipping near the ground is not advisable. Thus, crabbing with a last-second de-crab is the best option.

@xxavier Thank you for your reply. Then what's your opinion on my second question? Watching several crosswind landing videos on Youtube, I found a small number of airliners landed crabbing all the way down onto the runway without a last-second decrab.

You can embed links with [link text](url).

@lemonincider  With a crosswind, in order that the plane may follow the axis of the runway in final, you approach with the wings level and an big angle between the plane's axis and the runway. That angle has to be corrected at the last moment, before the wheels touch the ground. That 'instant' has to be as brief as possible, because during that small time, the plane moves sideways. Now, in order to reduce that angle (even to zero if the crosswind is not to strong) you may also roll the plane slightly to the crosswind. That may be advisable with high-wing planes, but no with low wing ones...

@xxavier So are you implying a touchdown on the runway in a crab attitude is the wrong crosswind landing technique? But I saw it used on some videos, and most of all, Boeing introduces it as one of the three crosswind landung techniques (although Airbus discourages using it).

@lemonincider  No... I'm not implying anything... Please read my last comment. I know quite well what I'm talking about, having done thousands of landings, some of them under very difficult wind conditions.

@xxavier I apologize if I was misunderstood. I didn't write my previous comment because I suspected your level of knowledge about flight but because I just wanted to emphasize that those techniques are being actually used by some airline pilots and get your opinion on that.

FWIW, in the 1990s in 747-100/200 aircraft I handled all crosswinds regardless of strength in the same manner: Maintain a crab down final, at the 50 foot call (radar altimeter) decrab as much as possible while lowering the upwind wind to not more than 5 degrees. That meant that in a heavy crosswind, I'd still have some crab left at touchdown.

First, I would say that the question should be between Crab technique vs sideslip technique. What the wikipedia article describes as De-crab technique is simply a quick transition from crabbing to a momentary sideslip as the wheels touch down. Generally, landing while crabbed is bad form, regardless of type or size of aircraft due to the side load on the landing gear at touchdown.
I was taught that side slip technique (where you fly with the down wind wing slightly elevated and use rudder to keep fuselage and wheels lined up with the centerline) is preferred because you don't have to do any last second adjustments right before touchdown. If you do this correctly, the turning tendency of the aircraft is mostly cancelled out by the cross wind component. Also, if you do this right, you touch down with upwind mains first, then downwind mains.
However, I was also taught that side slip makes passengers feel uncomfortable, and that is why airliners stay in the "crab" until last second.
As to your comment about airliners failing to de-crab, I've seen that too, I argue its just bad technique. Its difficult to properly execute the de-crab, it takes finesse and good timing.

Actually, landing while crabbed is a preferred technique with some airlines.

I could see that, assuming the crab is not too severe. I've felt it many times when traveling as a passenger. What airlines are you referring to? I'm curious to know if there is a threshold of crab angle.

I suspect @Terry's comment on the OP's question is the reason for some airlines landing with crab. The bank angle is limited to a certain angle that might not be sufficient for strong crosswind. I don't know if its preferred technique, but when I'm a passenger in an airliner that lands without de-crabing or whatever you want to call it, I always think to myself, "amateur." :) Terry explained it exactly right.

Most airliners are designed to accommodate reasonable sideloads on the landing gear during touchdown per the Part 23 requirements for transport aircraft.  Sideslippimg at touchdown creates a risk of contact with the engine nacelles and FOD ingestion.  Therefore most manufacturers and airline SOPs suggest touching down in a crab, then aligning with the runway centerline after touchdown.

It's surprising most manufacturers and airline SOPs suggest touching down in a crab. Do they provide any conditions where that method should be used, like a specific crosswind component?


text:
What is the difference between TAS and GS?
I'm looking for an explanation of true airspeed and ground speed.

The difference between them is the wind speed. TAS + Wind = GS

If you know what the abbreviations mean then this question answers itself!

TAS = True Airspeed = speed that you get on radar gun as airplane flies by, when radar gun is held by someone in gondola of balloon in same airmass (wind motion) as airplane.
GS =Groundspeed = speed that you get on radar gun as airplane flies by, when radar gun is held by someone on ground.
As an example: TAS of 200 knots and a headwind of 20 knots gives a GS of 200-20=180 knots.  That is: the plane travels at 180 knots over ground but the air is flowing past the plane at 200 knots.

Weird phone screw-up there!

Feel free to add via editing (or post own); I'm not emotionally attached to ownership of this answer :)

Edited to fix units and avoid issue with what you "feel" with hand being a better description of IAS than TAS.

Pythagoras would like to have a word with you about your "GS" definition.

@JacobKrall - ok I get it.  The radar gun should not be triggered until a/c is flying nearly directly away...

True air speed is the speed in relation to the mass of air you are moving in, and ground speed is the speed in relation to the ground.

Short answer.
TAS is GS without wind.
GS is TAS with wind factored in.
So, on a no wind day, TAS = GS


text:
What are typical ratios of galley carts to passengers?
What are typical ratios for the number of galley carts to passengers on a two meal long haul flight for First, Business, Premium Economy and Economy? This is for cabin layout planning. I found one a/c lessor using 1.0 for First, 0.41 for Business, 0.13 for Premium Economy and 0.1 for Economy. Is that about right?

Welcome to aviation.SE! Maybe you want to clarify your question a bit. Which galley cart sizes are you talking about? Your numbers seem pretty low for a full size trolley - only 20 meals in an Economy cart?

A full size ATLAS cart has 13 inserts on each side (front and rear). What does the "0.1 for Economy" in your question refer to?

Thank you for responding. The 0.1 for Economy means that one trolley cart feeds 10 Economy class passengers two meals on a 2 meal long haul flight. Similarly 0.41 for Business Class, means that one trolley cart feeds 2.5 business class passengers on such a flight.


text:
How long did it take to set up a portable runway?
How long did it take to set up those metal runways? Were the metal sheets spiked into the ground? How big were they? Also, how are commercial runways built?

What are you talking about? What "portable runway" are you asking about? Where was it built? When?

Welcome to aviation. SE! This question is sightly related. If you're new here please take the [tour] to see how the site works. We prefer one question at a time, for example.

Which runways?  That might help us answer the rest of your questions.

It really depends on "where".

You should remove the "also..." part of your question and ask that as a separate thread.

The last of your question is an whole question, you may find that most runways are made of asphalt and thus you can narrow this question to difference between runway and streets for building asphalt surfaces.

Google is your friend. Try it. "perforated metal airstrip"
https://en.wikipedia.org/wiki/Marston_Mat
"A runway two hundred feet wide and 5000 feet (1500 m) long could be created within two days by a small team of engineers."


text:
Why would my electric turn coordinator suddenly stop working?
The electric Turn Coordinator in our Cardinal stopped working and we would like to understand the cause.
It simply doesn't move at all, it remain fix.
The red flag is not on, I have double checked the circuit breakers as well.
What could be the cause to that?

The motor for the gyro in a Turn Coordinator runs off fixed frequency ac power. For this there is a circuit board in the unit that includes a solid state static inverter to convert the airplane's 12 vdc to ac (110 v at 400 hZ IIRC).  When they just die like that it's usually because the inverter or something else on the circuit board has gone south.

Thanks, is it a dead unit or can it be repaired ?

@user1064038 Most things can be repaired. Whether your unit can be repaired economically, or at all, depends on the exact fault. You should contact the manufacturer's nearest service agent.

If it's one of the newer cheapie plastic short-case TC's that started to appear in the 80s, it's not worth fixing and it's cheaper to replace I believe. If it's an older one with the long metal housing it might be worth fixing.

Regular fault is sticky pivot on indicator 'aeroplane'
Grease/oil hardens and as drive is from gyro gimbals via wire leaf spring 'plane doesnt move although gyro is trying to move it.
Degrease pivot,relube,test.


text:
What does BLU+ mean in a METAR?
I know that BLU is military code and means "Ceiling at or above 2,500 feet; Visibility at or above 8,000 meters".
ETSH 241320Z 19007KT 9999 SCT048 SCT160 BKN200 08/03 Q1008 BLU+
ETSH 241220Z 20005KT 9999 FEW050 SCT160 BKN240 08/03 Q1009 BLU+
But what does + at the end signify?

Per the German Meteorological Service, the + means a ceiling 20,000 feet or higher.

BLU: visibility>=8000m, ceiling 2500 - <20000 ft
BLU+: visibility>=8000m, ceiling >=20000 ft


text:
Why and how would I land straight-in from a circle-to-land approach?
I'm currently studying for an IR (US). One of the exam practice questions concerns an IAP having only circling minimums, and references 5-4-20(c) of the AIM, which reads:

Straight-in Minimums are shown on the IAP when the final approach course is within 30 degrees of the runway alignment (15 degrees for GPS IAPs) and a normal descent can be made from the IFR altitude shown on the IAP to the runway surface. When either the normal rate of descent or the runway alignment factor of 30 degrees (15 degrees for GPS IAPs) is exceeded, a straight-in minimum is not published and a circling minimum applies. The fact that a straight-in minimum is not published does not preclude pilots from landing straight-in if they have the active runway in sight and have sufficient time to make a normal approach for landing. Under such conditions and when ATC has cleared them for landing on that runway, pilots are not expected to circle even though only circling minimums are published. If they desire to circle, they should advise ATC.

I'm having trouble understanding the bolded sentence. What does it mean to land straight-in from an approach that is more than 30 degrees from runway alignment?
I've been understanding a circling approach as something like a pattern landing where you start the maneuver once you have passed the FAF and have - and can keep - the runway environment in sight. But this seems to imply something different. What am I missing? What does "a normal approach to landing" mean here?

The sentence before the one you bolded, with my bolding applied, says:

When either the normal rate of descent or the runway alignment factor of 30 degrees (15 degrees for GPS IAPs) is exceeded, a straight-in minimum is not published and a circling minimum applies.

So you can have a "circling approach" that is lined up straight in to a runway, but with only circling mins, not straight-in minimums, published.  This could be driven by the need for a high FAF altitude, high enough that you can't get from that FAF at that altitude down to the runway, with a descent rate that's within the TERPS criteria.  So they build an approach that assumes you maneuver to lose the excess altitude, and give you circling mins so that you can.
However -- and this is what the exception that you bolded in the question is about -- if you're in, let's say a STOL airplane, you may very well be able to lose the excess altitude and be established on a normal visual glidepath to the runway with ample time to make a "normal approach and landing" without any S-turns or other maneuvering required.  And in that case you're absolutely allowed to fly the approach straight in.  The guy behind you in a Lear Jet may not be able to do the same thing that you did, and the TERPS descent profiles criteria are written to guarantee that if he has straight-in mins, he CAN get from the FAF at its crossing altitude to the runway without having to use what would be, for him, a dangerously high descent rate (angle).  But in the STOL aircraft, a steep descent is perfectly normal, so you can go ahead.  The Lear shouldn't try to mimic the Maule's descent profile, but that doesn't mean that the Maule has to mimic the Lear's descent profile.

Is this really just about STOL? That seems unusual.
There's two cases (plus any combination) that seem to apply. One is a >30 deg heading change from approach to runway. The other is a steep descent. I can see how in a 172 you could do a 1000'/min descent to land no problem. But in the >30 deg case, what does "straight in" actually mean here? Or does it just not apply in that case?

It isn't about STOL, but rather 91 vs 135/121 operators. The latter are required to have a stabilized approach by a certain altitude or go missed, whereas the former are limited only by the "careless or reckless" rule and thus have a lot more freedom in how they comply with intentionally vague rules like this.

@StephenS, but what count as stabilized approach still depends on whether the aircraft is certified for steep approaches and how steep approaches are permitted, doesn't it?

@JanHudec Steep approaches can be stabilized, such as at LCY, but it seems unlikely in the case of circling.

If you break out of the clouds with sufficient altitude, you can line up with your desired runway of use before reaching the MAP. You can only do this if you can effect the landing using normal maneuvering procedures. Breaking out of the clouds before the FAF with 10sm or more visibility would be a perfect scenario to deviate from the lateral guidance and line up for the straight-in landing.
You can also request a Contact Approach per AIM 5-4-25.

Aside from the contact approach option, which rumor has it no one ever actually asks for, would you have to request a visual approach instead or cancel IFR? My understanding has been that you're not supposed to deviate from the approach course until the MAP.

@FosterBoondoggle -   Once you are on the approach, you are communicating directly with the tower. You could request anything you want. They are there to help you. Just make sure you stipulate that you are in VMC. That way they do not mistake your intentions for flying a Charted Visual Flight Procedure.  See   https://www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/info/all_infos/media/2011/InFO11003.pdf

@FosterBoondoggle - According to the Aeronautical Information Manual (AIM), a Visual Approach authorizes a pilot flying under Instrument Flight Rules (IFR) to proceed visually to the airport while remaining “clear of clouds.” Clearance for the approach is predicated upon the pilot having either the airport or the preceding identified aircraft in sight and the airport reporting a ceiling at or above 1,000 feet and a visibility of 3 miles or greater.

Here is note 1 from 4-8-1 of 7110.65:
Clearances authorizing instrument approaches are issued on the basis that, if visual contact with the ground is made before the approach is completed, the entire approach procedure will be followed unless the pilot receives approval for a contact approach, is cleared for a visual approach, or cancels their IFR flight plan.
This sounds like a separate approach clearance from the original circling clearance.

Found that info here, which also discusses the exact same point:
https://aviation.stackexchange.com/questions/1828/when-flying-a-circling-approach-is-it-permitted-to-begin-the-visual-circling-se

@FosterBoondoggle - Is it a separate clearance? In some cases, yes. And, in others, no. We have an IAP at my local airport that has the MAP right at the beginning of the downwind leg of RWY36. This IAP has only circling minima. Albeit, 230 feet lower than the traffic pattern altitude. If I break out of the clouds before reaching TPA, I am not going any lower than TPA until I am abeam my touchdown point. This will not require another clearance besides clear to land if it has not already been given.

@FosterBoondoggle - if on the other hand, I am cleared to land on RWY18, I could effectively side step to the right (RWY 36 is RP) as long as I break out of the clouds at least 2 miles before the MAP. My instructor would do it in less than 1 mile. Then again, it’s a 7000 foot runway in a C172. Just as long as I remain above the decision height until I can stay out of any clouds and retain suitable visibility. Typically, if the clearance is for 36, ATC will give the instruction to circle East of the field. If for 18, they will instruct to keep the circle North of the field. No further clearance

I think there is some term jumbling here that can likely be cleared up with the statement:

Circling minimums do not necessarily imply you are going to execute a "circle-to-land" maneuver

A circle-to-land maneuver is a low altitude, close to the field, turning maneuver that allows you to use an approach set up for a given runway but ultimately land on another runway.
Circling minimums are added to an approach when the design and topography of the area can guarantee/meet the requirements for a pilot to execute a "circle-to-land" maneuver. This is covered in the FAA's approach handbook:

The circling approach area is the obstacle clearance area for aircraft
maneuvering to land on a runway that does not meet the criteria for a
straight- in approach. The size of the circling area varies with the
approach category of the aircraft... ...A minimum of 300 feet of obstacle
clearance is provided in the circling segment. Pilots should remain at
or above the circling altitude until the aircraft is continuously in a
position from which a descent to a landing on the intended runway can
be made at a normal rate of descent and using normal maneuvers. Since
an approach category can make a difference in the approach and weather
minimums and, in some cases, prohibit flight crews from initiating an
approach, the approach speed should be calculated and the effects on
the approach determined and briefed in the preflight planning phase,
as well as reviewed prior to commencing an approach.

This does not mean that you need to execute a Circle-To-Land maneuver to land, it simply means that you can if you apply the appropriate minimums and it is the maneuver that will get you to the favored runway.
Lets look at a real world example. C66/Monmouth Municipal Airport has a single VOR/GPS-A approach with only circling minimums.

(source)
Now let's say the wind is favoring a landing on runway 21. The Approach does not meet the less than 30 degree offset requirement so straight in minimums can not be added to the design. The circling decision altitude is 1360 which you are likely to cross well outside of 2 miles from the runway. If you cross this altitude and have the runway environment in sight there is nothing precluding you from effectively joining what would be a final approach and flying a straight in approach. which you will have plenty of time and distance for (lets say your flying a 172 coming in at 75 Kts).

Note: Historically the high cost of physically installing a VOR/NDB etc meant that not all of them could align nicely with runways and off-set approaches were more common, leading to the need for circling. With the advent of GPS and the lower cost to have two straight in approaches to a field this has be come less common.

What does "straight in approach" mean in a context like this where you'd basically fly a modified left base, or even a downwind & base (in your rwy 21 example) at 700AGL about 2 miles from the threshold (for a 3deg glideslope) before turning final? This really highlights the terminology puzzle I started with. Does one call a landing pattern involving a base leg close to the field "straight in"? I assume almost everyone is flying their short final "straight in".


text:
How does a TACAN signal change with bearing from the station?
In the TACAN system , how does a change in bearing , would translate to a change in the time (or frequency) domain.
I'll try to elaborate:
I'm aware , of the TACAN operation in general.
let's say that I'm 270 degrees (referance to north) and 180 degrees (referance to north) , how would this change reflect on a Scope or on a spectrum analyzer if at all (of course I mean in the analog signal).

Take a look here for what scope traces would look like at various times.  I am not going to copy the page.  http://www.opticfox.com/2a4x2/tacan-fun.htm

hello Cross , thank you for replying , I have went over that website several times , unfortunately, I could not see the change on scope from bearing differences,
It explains it work in general , I'll try to clarify my question , what I'm trying to get is a variable that I can track which could lead me to calculating the bearing information may it be the pulse amplitude or envelope frequency.

Change in bearing doesn't change frequency. The ground station always transmits  pulses on a single assigned frequency. The illustrations in the link from @CrossRoads only show what would be seen by a receiver at 000 magnetic. For other bearings the whole envelope shifts while the reference bursts stay still. The antenna illustration shows reflectors on spinning drums that create an envelope whose phase difference from the reference bursts depends on bearing. My markup of the diagrasms in the link (MRBs are blue):

A TACAN or VOR station actually transmits two signals:

a reference signal whose phase shift is independent of azimuth angle
a signal that is phase shifted, where phase shift (0-360°) equals the azimth angle

At the receiver side the phase difference of both signals is determined. The phase difference equals the bearing.
There are various ways of generating signals whose phase shift equals the azimuth angle:
e.g. in AM: by mechanically rotating a directional antenna
e.g. in FM: rapidly switching from one antenna to the next one among a set of antennas placed on a circle.


text:
What, as far as the FAA is concerned, is required for Ag Application?
There are lots of "you need this..." comments, but I'm wondering what is required, legally, by the FAA?
A Commercial Rating, of course.  Flying for money and all.
A Taildragger Endorsement because the plane will probably be a TD.
A High Perf Endorsement because the plane will have over 300hp and very likely electric flaps - but maybe not cowl flaps.
But the FAA doesn't care about Insurance, does it?
And really it doesn't care about the chemicals either, does it?  I mean in their statutes.
The Chems have state and fed guidelines, of course, but beyond the purview of the FAA.
Are there other ratings or certifications involved under the FAA?

From the context it is obvious you want to be a crop duster, but would you mind clarifying what you mean by "Ag Application"?  Is this something you apply to the FAA as a prerequisite for employment?  Because otherwise just what you listed ought to be all that is needed from their standpoint.  Of course your prospective employer would have to agree...

I'm told it's not called Crop Dusting anymore.

I already said I realize it requires a Commercial Ticket.      In fact, I said "Commercial Rating" of course"  So, no, it's not a dupe of that question which we already know.

Perhaps the other question isn't an exact dupe but the currently accepted answer does point you to AC 137 in addition to answering the certification part. I don't know if you've already read that but it's probably what you're looking for. And as that answer mentions, a commercial certificate is not required for aerial application if it's on your own crops.

So if your answer is simply "go read 137" I can do that.  I was hoping someone would actually know the answer.  So far the first answer said "what you listed ought to be all that is needed" which I kind of opened with, but was hoping someone would actually know.

"I'm told it's not called Crop Dusting anymore."  I guess "aerial application" is more politically correct or somehow less offensive?!  Call it what you want, I call it crop dusting.


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What is the FAA's definition of a "multi-engine aircraft" that requires a multi-engine rating?
In a Facebook group I stumbled over this nice little picture:

Also there was a discussion about the type rating of this plane, especially if it classifies as a multi-engine plane. It is a Colomban Cri-Cri (MC-12/ MC-15).
What I've learned from the discussion and this document is, that this is an experimental plane and doesn't fall in the classic regulations and that UK's CAA doesn't require a multi-engine rating for the pilot. I think that answers the original question.
But in this thread and another discussion on another website I saw a lot of discussion about what regulations would apply if it would not be an experimental craft and what the FAA would say about it.
So my question is: There have to be specific requirements for a plane to require a multi-engine rating. To stay specific here, let's only look at the FAA. (I come from Germany, so if there would be any differences it would be interesting, but isn't required for this question)
Some people cited different paragraphs, but it seems none really applied and there was a lot of confusion. But I doubt that there is anything regarding aviation that is not tightly regulated, so I think there must be specific rules.
There is already a similar question regarding the Cri-Cri on this page here, but it has a different focus and it was stated that there would be no reason one couldn't file flight time in this plane as multi-engine flight time, but nothing precise.
So, what are the requirements for an airplane to be considered multi-engine and require a multi-engine rating to fly it? Also, why is this airplane considered single engine from a pilot perspective?
Note: I'm not a pilot, only a flight-simmer and aviation enthusiast.

Your question is confusing to me, are you asking for the requirement for a pilot to attain a multi-engine rating, or what an airplane needs in order to require a pilot to have a rating to legally fly it?

I'm asking about the requirements for an aircraft to be considered a multi-engine plane (which requires a pilot with multi-engine type rating) and why there seems to be confusion about this plane regarding the type rating.Sorry, I don't know how to express it otherwise

That makes sense now, I've taken the liberty of editing your question to reflect that, feel free to edit it yourself if you would prefer stating it a different way.

On a personal note I have seen one of those up close and they are even smaller than the picture may make it seem. The wing didn't even reach my knees!

I couldn't find any definition of "multiengine" anywhere in the FAA's regulations or on their website. The closest thing I did find is from the Airplane Flying Handbook, chapter 13, Transition to Multiengine Airplanes:

For the purpose of this handbook,  a “small” multiengine airplane is
a reciprocating or turbopropeller-powered airplane with a maximum
certificated takeoff weight of  12,500 pounds or less. This discussion
assumes a conventional design with two engines—one mounted on each
wing.

Obviously there are multiengine aircraft with three, four or more engines too. I assume that the FAA doesn't define the word "multiengine" because it has the 'plain English' meaning of that word, i.e. more than one engine.

and my guess is they define "small multiengine" as twin engine because it was inconceivable to them that something that small would require more than 2 engines :)

Pondlife is correct.  The Cri-Cri would be considered a multi-engine airplane because it has more than one engine.  It does not require a type rating as it does not meet the requirements to have a type rating issued to the airman.  It does appear there is a jet powered MC-15 variant that would require a type rating.
The following ratings are placed on a pilot certificate (other than student pilot) when an applicant satisfactorily accomplishes the training and certification requirements for the rating sought:

§ 61.5 Certificates and ratings issued under this part.

(b) The following ratings are placed on a pilot certificate (other than student pilot) when an applicant satisfactorily accomplishes the training and certification requirements for the rating sought:

(7) Aircraft type ratings -

(i) Large aircraft other than lighter-than-air.

(ii) Turbojet-powered airplanes.

(iii) Other aircraft type ratings specified by the Administrator through the aircraft type certification procedures.

The reason there are different certificates for single and multi engine airplanes really has nothing to do with size.  It's about the different flying characteristics, primarily what to do if one engine fails.  Presumably the Cri-cri would have the same problems.  It's why you can get a multi-engine rating that's limited to centerline thrust, if you want to fly something like the Cessna Skymaster.


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What's the precise meaning of "landing south (north, east, west)" in STARs?
"JetBlue six zero two leaving flight level two one zero descending via the Ivane Two arrival landing south."
Does "landing south" here mean the aircraft will be landing on the runways north to south?

"Landing south" means the planes are facing south as they land. Depending on conditions, they could come from the opposite end of the runway, and would be "landing north." This is also referred to as "south flow/operations."
If you look at a chart for the IVANE FIVE shown below, you can see why this is important. The runways at KCLT are primarly oriented north/south. The aircraft will enter the approach at MAJIC from the northeast. If landing south, the arriving airplane will fly IVANE BABZE HEELZ and needs to be at 6000 feet when they reach HEELZ north of the airport. Approach control will then turn them south to land. If landing north, they will fly from IVANE to GIZMO and follow the approach down to the south, and don't have to be at 6000 until they get down to ESENE. After reaching JATAB approach turns them north to land.
Telling the pilots which direction they will be landing lets them know which route to follow on the approach and helps them plan their descent. If approach hasn't provided a runway yet, they can also know which runways they can plan for.

Source. This is the best I could find for the IVANE arrival. The MAJIC ONE isn't RNAV, the CHSLY THREE would seem to be the applicable RNAV procedure from the northeast.

The IVANE arrival has been discontinued and replaced by the CHSLY arrival.

Landing south means that they will be using a southerly heading runway. I.e. landing on rwy 18 rather than 36.
The landing directions will be indicated on the STAR. For example the chart below for Charlotte.

Depending on which runways are in use the flight will take a different branch of the STAR. Since they aren't given a specific runway assignment yet they will report in with the general direction they expect to be landing. They are usually given this by the en route controller. If not the ATIS will tell them what runways are in use. If the northbound runways (36L/R/C and 5) are in use, they are "landing north" so when they reach waypoint MANGY they will turn left to a heading of 273° and expect the controller to give them vectors after GATEE waypoint. If the southbound runways are in use they will be "landing south" and will continue on the STAR until INNOR wp. This lets the controller know what they should expect the aircraft to do until they are told differently.
Usually when they check in they will be given a specific runway assignment, but it's possible the controller won't have a specific runway yet, so they will follow the correct branch of the STAR until they are given that assignment. That's why they have the general "landing north" or "landing south" designations.
In this example, if they are landing south they need to have a specific runway assigned by the time they reach INNOR because they must either turn right toward rwy 23 or continue straight toward rwys 18L/R/C.
It is possible, due to a shift in wind or noise abatement change, the airport could have changed directions (or the en route controller could have given them incorrect info). That's why they must tell the controller at check in which direction they are going to go.

One arrival may have multiple routings after a branch point, and when ATC assigns the arrival and the descend-via clearance, they have to specify which branch is to be flown.
As an over-simplified example, let's say that the arrival starts at AAA, then flies east toward the airport to points BBB and CCC, which is the branch point.  When the airport is landing to the south, aircraft turn north (i.e. onto a downwind leg) and proceed to point NNN and OOO, and then a vector toward the (southbound) final approach course.  When the airport is landing to the north, after CCC the arrival would have the aircraft turn south (again, onto a downwind leg) and fly to point SSS and TTT, and then a vector toward the (northbound) final.  Each of these points might have an associated altitude and/or airspeed, and the clearance to "descend via the ___ arrival landing north" and "... landing south" tells the pilot which set of points (AAA-BBB-CCC-SSS-TTT-vector, in the "landing north" case, or AAA-BBB-CCC-NNN-OOO-vector in the "landing south" case) he's cleared to fly, along with their associated speeds/altitudes.


text:
What drives the compressor before the turbine provides power?
I understand that the power extracted from the turbine is used to drive the compressor which sucks and squeezes air sent to the combustion chamber, and the cycle continues.
But initially the compressor has to suck in air! What drives it at this stage before the turbine takes over?

Are you asking how an engine is started? Then How are turbine engines started? might help.

Turbine engines are spun up to idle speed using a starter.  This is typically in the form of an electric motor for smaller turbine engines and APUs and pneumatic powered starters for large turbine engines.  Once the gas core is spun up to a minimum speed, typically around 12-20% maximum core speed, fuel is introduced and ignited, causing a self sustaining combustion and the engine core spins up to its idle speed, typically about 50% - 60% maximum speed, before the starter cuts out.  Care has to be taken not to introduce fuel to the engine prior to reaching these speeds as the engine can overheat during startup and be seriously damaged (this is about the only disadvantage of aviation gas turbines).

You don't really have to worry about screwing up a start with FADEC engines. Most of them now you just push a button and away it goes.

IF your aircraft is power by wire, that is.

@JohnK Still, if you want to know how it works, How are turbine engines started? gives a really helpful overview and How is bleed air used to start a jet engine? shows what "pneumatic powered starters" are.

Not to worry; I'm well acquainted with starting systems. My point is the disadvantage of crew member being able to ruin an engine starting it is eliminated with FADEC.

And even then, you’d better closely supervise the process, since, if it goes wrong, you only have seconds to bring the engine to idle cutoff before it overheats.

Yeah, will FADEC recognize and shut down a hot, hung, or wet start?


text:
What are the considerations to make when altering logbook entries?
As I move through my flying experience, the possibilities for logging time change.

Before I was rated, my time with an instructor is logged as dual only.  Most of these entries were made by various CFI's.
After being rated, FBO checkouts and flight reviews were logged as PIC and dual. These entries were often made by myself and signed by the CFI.
When receiving instruction for endorsements (tailwheel, high performance, complex), entries were usually made by the CFI.  It appears that most of the time, the instructors making the entries favored the idea that until I had the endorsements, they would leave the PIC column blank and log only dual received.

The answers to This Question lead me to believe that I could indeed have logged this as both dual and PIC, since I was rated for the category and class for which I was flying.
Here is the question:  What consideration should be given before I go back and add PIC to the flights which were filled in by someone else?  Should I leave it alone or claim the time as PIC since I was both "sole manipulator" and rated in that category and class.

As a side note, my primary tailwheel instructor was all over the place.  On our first flights together, he put the time in PIC, then switched to dual only.  I think this was just an oversight, where the main body of my question deals with augmenting entries which were made the way they are clearly on purpose.

What do you mean by "consideration"? Are you asking if it is legal to manipulate your historical logbook entries? Legal to alter something that a CFI endorsed? Ethical? As a side note, a good CFI will know what can be logged as PIC and make sure you make the correct entry before they sign it...

Yes, I am interested if it is legal, I am interested to know what constitutes a "statement" as my pages have a space for me to sign confirming that all statements by me are true.  If I add time to the PIC column, am I tampering with someone else's statement, or could I initial to clarify that the clarification belongs to me.  Surely a good CFI will know what can be logged as PIC and look over my entry before they sign it.  At least Three that I can think of decided not to make an entry in my PIC column.  Perhaps the prevailing thinking has changed over time.

I couldn't find any specific regulations, but correcting errors or omissions in the time logged is fine. You should never change an actual endorsement, though.
To take a simple example, if your CFI wrote in 1.1 hours instead of 2.1 hours then I assume you wouldn't hesitate to correct it later because it's an obvious error of fact. In the same way, if your CFI didn't write in PIC time when he should have then there's no problem if you add it yourself. Provided of course that you're sure that you were indeed allowed to log PIC time for that particular flight.
If you want, you could add a comment or keep a record of changes on a separate sheet in case someone ever questions it. But for what it's worth, I have a number of corrections in my logbook and no one has ever asked about them. There's a high degree of trust involved in logging time because it's so difficult to verify the information independently.
But you shouldn't touch an endorsement. Only an instructor can make an endorsement and even if there's some mistake then you should ask the instructor to enter a new one rather than change it yourself. Endorsements get much more attention that time logged, and I think it would be tough to explain why you changed one yourself.
Finally, you mentioned your instructors' "thinking" or "ideas" about logging PIC time. I don't want to make assumptions about their intentions (and I'm not a CFI), but logging PIC time is defined by regulation, not by what individual instructors think. If you're still in contact with those CFIs, it would be a great topic to discuss with them. Perhaps they didn't deliberately omit the PIC time, they just forgot or overlooked it. Or maybe they did have a reason, but in that case they should at least be able to explain it to you with reference to the regulations.

Changing an endorsement is different from changing how time is accounted.


text:
How fast do four Tire-Propellers have to rotate to lift 2000 lbs?
I just saw this come out, Goodyear's Tire-Propeller Concept – a combination tire that can also act as propeller (well, more like a ducted fan I guess).
There's a neat video that goes with it, describing how the fan blades need to bend while being used as a tire. (Otherwise, one winter in New England would take them out!)
Any ideas how fast something with say four 18 inch diameter wheel/propellers, and 3-4 inch fan blades, would have to spin to generate enough downforce to actually get 2000 pounds off the ground?
The weight is the vehicle with 4 motors, 300 pounds of batteries, 600 pounds of passengers & baggage; comparable to my 2500 lb max gross weight airplane, but with weight savings of no wings or tail structure, and batteries vs fuel. 4 motor/fans, and allowing (requiring?) the lift off process to be from a stop, so that all 4 motor/fans could be rotated from road use to propeller use (vs rolling on 2 like the video shows). I imagine 14,000 RPM or some high speed would make quite a lot of noise, compared to the takeoff noise of my 180 horse power engine and 86 inch propeller.
Edit: This rim-driven propeller wheel doesn't look like it would have much total blade are for moving air. That would take even more speed, wouldn't it?

The Moller Skycar seemed quite noisy for a comparison.

Your going to get supersonic tip somewhere around 13500RPM which would be limiting for a rubber propeller

Got to imagine that would be pretty irritating to listen to if nearby.

Let's do a back-of-the-envelope estimate. As a simplifying assumption, assume that a propeller generates lift by accelerating air through an opening of a particular size, at one particular speed. The formula for the amount of lift generated in this case is:
$$\text{Lift} = \text{Opening area} \cdot \text{Air density} \cdot \text{Exhaust speed}^2$$
For each propeller, the needed lift is 500 pounds force, and the area of each opening is $\pi \cdot (\text{$9$ inches})^2$.
So we can calculate the needed exhaust speed using Wolfram Alpha: square root of (500 pounds force / (density of air * pi * (9 inches)^2))
The answer comes out to 230 mph. That's the speed that the air has to move downward through the rotors. I don't know how fast the propeller will have to move in order to make this happen, but it will be a comparable speed.
The amount of power required can be found by multiplying this number again by the amount of lift. According to Wolfram Alpha, that comes out to 307 horsepower (229 kilowatts) per rotor. So about 1,200 horsepower for the entire aircraft, if the rotors were 100% efficient.
Good luck with that.

1,200 HP ~ 1 PT6A turbine engine, so it seems in the neighborhood of reasonable. The AW609 tiltrotor's got 3,880 HP total.

Hmm, that doesn't seem reasonable to achieve with the simulations shown in the video, especially as one gets the impression the tires are being rotated from the rim using a magnetic repulsion kind of idea. Or maybe that was just the bearings, to allow high speed revolutions. Gotta get braking in there too somehow for road use.

The Williams FJ33 https://en.wikipedia.org/wiki/Williams_FJ33 used on the Cirrus jet FJ50 "produces between 1,000 lbf (4,400 N) and 1,800 lbf (8,000 N) static thrust", so is it correct to say one would need 2 of those to make 2000 pounds force to count the 2000 pound weight of the vehicle including 600 pounds for the motors themselves?  The separate quad copter/road wheels sounds more feasible.


text:
Why was the Concorde painted white and not black?
It's well-known that the stated reason the Concorde was painted predominantly white was to mitigate heating problems.
However, given that the source of the Concorde's thermal woes wasn't excessive exposure to solar radiation, but, rather, direct conduction and convection of compression heat, I'm confused; in that case, shouldn't the Concorde have been painted black (or nearly black), like the SR-71, to better radiate heat away?

Even white paint can still be effectively "black" at the long infrared wavelengths that will comprise the dominant radiative wavelengths at the temperatures the hull will reach.  I'm not sure if this is true of Concorde's paint, but plenty of materials "look" different in the infrared than they do in the visible.  A silicon wafer, for example, looks opaque dark grey to us but just a tiptoe into the infrared it is rather more like a transparent window.

The SR-71 was subject to the Rule of Cool.

Concorde's average skin temperature was 92°C (365K). Calculating the black body radiation using the Stefan Boltzmann law we get 1006W/m². This the maximum heat flux possible with perfect radiation, and very similar to the heat flux of solar radiation, which is also about 1kW/m² at the earth's surface in the absence of clouds (and a bit higher at Concorde's typical cruising altitude.)
However, as others have pointed out, at these temperatures Concorde would radiate in the far infra red, and it is perfectly possible to have a selective paint that appears white in the visible region (reflecting much of the heat of sunlight) while also radiating in the infra red region.

+1 Related (physics wise): Why are RTGs different colors? and also What is the function of this array of what looks like mirrors on TESS?

I know a little about selectively emissive surfaces, and as far as I can tell the effective ones are more recent than Concorde's design.  Some materials can obtain some benefit fairly simply, but building them into a paint isn't trivial

There is a discussion on it here that's worth reading but in short the requirements were just different. A few of the key points,

The black color on the SR-71 offered some night camouflage in addition to its heat dissipation
The Concorde had an Aluminium airframe while the SR-71 had a primarily titanium airframe which could lead to different coating types.
The Concorde was a commercial aircraft many of which are often painted white thermal benefits aside they may have simply been keeping with what they usually did.
The SR-71 flew substantially faster than the Concorde and had different thermal requirements.
The hottest point on the Concorde was the nose 127°C which was actually cooled by fuel being pumped through as a coolant. The hottest point on the SR-71 was the cockpit window which cooked in at 327°C again, very different requirements thermally.

I would not have expected the cockpit window to be the hottest part on the SR-71. Excellent references.

The thermal conductivites of aluminium and titan make a big difference. Pure Titanium has 22 W/mK and Dural has 147 W/mK. This means that Concorde's surface could distribute the thermal load between hot and cold spots much easier than the SR-71's.

@ke4ukz: I'm guessing it's partly because the SR-71's canopy sticks out into the airstream and causes a lot more air to get bunched up and compressed in front of it than the other parts of the SR-71.  Also, it isn't, strictly-speaking, the hottest part on the SR-71 - that honour goes to the engines, the hottest part labelled in that diagram of which cooks in at 1050 F, and the nozzles of which are unlabelled, but, going by the colour-coding of the diagram, look like they might go up to 1200 F or even hotter.  :-P

@Dave, your link to the temperatures of the SR-71 is broken. I replaced it with one that I think is the same (it shows the same temperature at the cockpit window)

The Blackbird was black so it could absorb radiation, not so it could emit radiation. Look at the Blackbird's predecessor, the A-12, it is fairly easy to find pictures of the A-12 with polished or partially polished finish. The Blackbird and A-12 moved to a radar absorbent black finish for reasons of observability, flying at the edge of space means a darker surrounding than lower in the atmosphere so the camouflage requirement is different than say a fighter jet. Any thermal emissions that do occur do so well outside the visible spectrum.
To reach the point at which it is beneficial to thermally dissipation for the aircraft to be painted black is to reach the point that the aircraft emits more energy as radiation than it absorbs in the visible spectrum. At that point the black aircraft would be brighter than a white aircraft.

@XRF the color of the paint has very little to do with its radiation and in extension stealth characteristics. The black paint as in Dave's answer had to do almost exclusively with heat emission/absorption. And in terms of your observability point, the SR-71 and variants of cruised over enemy airspace so high that even with a bright coating of paint, it would be difficult and pointless to attempt to acquire it visually. Keep it mind that even seeing it on radar (which the Soviets were capable of with their newer radars) doesn't nearly mean being able to prove its existence NOR shoot it down.

@Jihyun I edited to increase clarity. Thermal emissions at these temperatures (and radar to be fair) occur outside the visible spectrum. The SR-71 evolved from the faster A-12 with the goal of reducing observability (An A-12 was hit by a missile). The paint was radar absorbent and covered the entire body because of that, thermal concerns were only important in a limited number of places. Observability is not limited to acquisition either, it is harder to get a good image of a low contrast subject. The U2 moved from grey to a similar paint scheme around the same time for the same reasons.

Yes I have heard of that close-call incident as well. You picked my curiosity. I found that the Vietnamese had similar hardware as the Soviets, but as a whole were much less capable at using it, so (in parallel with the official declassified report) I would assume that they could barely detect enough of a signature for a lock, instead extrapolating a lead and using a shotgun technique in the hopes of a hit, as the Soviets did with the earlier U-2 overflights. Also, just keep in mind that the U-2 flew at over 10,000 ft lower than the SR-71 and variants.

Good question. There are two main reasons for the Concorde's specific coloring: Heat absorption and heat emission. The key to its color scheme is in the materials used in construction of each plane.
The Concorde was made of aluminum, which emits heat far more quickly and effectively than the SR-71's titanium skin. Contrary to popular belief, the plane will become ductile and lose structural integrity at far lower temperatures than the metal's melting point, and preventing the metal from reaching these temperatures is a key reason for the paint colors of each aircraft.
Aluminum becomes ductile and unacceptably weak at higher temperatures, but would rarely reach them at the Concorde's cruise speed, as the metal reflects/releases sufficient heat so that the paint can can do a more proactive job of keeping heat absorption at a minimum. If titanium had similarly good heat dissipation capabilities then I am confident that it too would have been white.
However, titanium at speeds around the Blackbird's cruise range would absorb far too much heat for it to release, so the black paint would actually be superior in terms of heat dissipation to compensate for titanium's natural characteristics. Short answer shorter, the aluminum on the Concorde didn't get hot enough for the aluminum to lose integrity, so white was the better option in terms of preventing the metal from reaching those critical temperatures.
The SR-71 however could not release heat as quickly as aluminum, so the paint was designed to aid it in that regard. Hope this helps, sorry about the formatting I am in a rush so if there was anything conceptual I left out then please comment.

What do you mean "dissipate heat"? conduction? convection? radiation?

Concorde was a civilian commercial vehicle. It's mission is not 100% flying, but also embarking and disembarking of passengers, waiting for ATC permission, etc. This means, it spend considerable time, on the ground, on low power, not heated by the airflow - but heated by the sun. For this part of the mission, white paint is vastly superior.
SR-71 was a military aircraft and it was optimized for one thing only - the flight. Sunbathing at the airport was not an issue, it was kept in a hangar for as long as possible anyway.